The Myelencephalon (or medulla)
is the posterior portion of the brain stem. Not surprisingly then, the
medulla is composed largely of tracts carrying signals between the rest
of the brain and the body. An interesting part of the myelencephalon from
a psychological perspective is the reticular formation. It is a complex
network of about 100 tiny nuclei that occupies the central core of the
brain stem from the posterior boundary of the myelencephalon to the anterior
boundary of the midbrain. It is so named because of its netlike appearance
(reticulum means "little net"). Sometimes the reticular formation
is referred to as the reticular activating system because parts of it seem
to play a role in arousal. The various nuclei of the reticular formation
are involved in a variety of functions, however  including sleep,
attention
(definitely important for language), movement, the maintenance of muscle
tone, and various cardiac, circulatory, and respiratory
reflexes. Accordingly,
referring to this collection of nuclei as a system can be misleading.
Generally, the myelencephalon does not play an important role in language
production or comprehension.